The present invention relates to a tool assembly with coaxial/universal coupling and, more particularly, to a tool assembly selectively providing coaxial or universal coupling by utilizing one or two C-clips.
A type of tool assembly allowing coaxial/universal coupling includes a tool mount having a hole in an end thereof. A tool shank includes an end having a rounded engaging member received in the hole. A C-clip is mounted in the hole to retain the engaging member in the hole. The other end of the tool mount can receive a bit or engage with a driving device. The other end of the tool shank can engage with a driving device or a socket. The hole of the tool mount includes a plurality of flat surfaces each having a recess. The engaging member includes a receptacle receiving a ball and a spring biasing the ball to engage with one of the recesses, positioning the engaging member in the hole while the tool mount is coaxial to the tool shank. The tool shank can be moved away from the tool mount to disengage the ball from the recess and then pivoted to a position at a desired acute angle to the tool mount. Thus, the tool mount can be coaxial or at the desired acute angle to the tool shank while allowing joint rotation of the tool mount and the tool shank regardless of the angular relationship therebetween. An example of such a tool assembly is disclosed in U.S. Pat. No. 7,278,342. However, formation of the receptacle and recesses and mounting of the ball and the spring in the engaging member of the tool shank are time-consuming and increase the manufacturing costs. Furthermore, the engagement of the ball and spring in one of the recesses provides only one biasing point to maintain the position of the engaging member in the hole. The resulting positioning effect is unreliable.
Thus, a need exists for an inexpensive, simple tool assembly with coaxial/universal coupling. There is also a need for such a tool assembly with multiple contact points to maintain the coaxial position.